1. Field of the Invention
The invention relates to a hybrid vehicle that includes an engine and a motor, and runs using at least one of the engine and the motor used as a drive source and a control method for the hybrid vehicle. The invention relates to a warm-up control of a catalyst for purifying exhaust gas of the engine.
2. Description of Related Art
Japanese Patent Application Publication No. 2002-130030 (JP 2002-130030 A) describes that, in the startup of an engine provided with a catalyst in an exhaust gas passage from its cold state, by setting a target rotation speed during first idling in the cold state of the engine to a higher value as the misfire rate of the engine is larger, a combustion state during the first idling in the cold state of the engine is improved, the warm-up of the catalyst is accelerated, and the amount of emission of hydrocarbon (HC) caused by the misfire of the engine is reduced.
Japanese Patent Application Publication No. 2012-40915 (JP 2012-40915 A) describes that, in a hybrid vehicle, during the warp-up of the catalyst, an engine rotation per minute (RPM) during a catalyst warm-up operation is set to the lowest RPM during normal running and moreover an output torque is set to 0 or a value slightly higher than 0. In addition, JP 2012-40915 A also describes that the ignition timing of the engine is retarded relative to the ignition timing of the engine during an efficient operation, and the catalyst warm-up is thereby accelerated.